Intermittently connected optical fiber ribbon

ABSTRACT

[Problem] When a surface of the optical fiber ribbon is rough, the microbending loss is increased due to the irregularities formed on the surface of the optical fiber ribbon. 
     [Solution] An intermittently connected optical fiber ribbon of the present disclosure, includes: a plurality of optical fibers arranged in a predetermined direction; and connecting portions that intermittently connect two adjacent ones of the optical fibers. A peripheral cover portion formed of resin configuring the connecting portions is formed on a periphery of the optical fibers. An arithmetic mean roughness Ra of a surface of the peripheral cover portion is 0.41 μm or lower.

TECHNICAL FIELD

The present invention relates to an intermittently connected opticalfiber ribbon.

BACKGROUND

Patent Literatures 1 to 3 describe an optical fiber ribbon includingmultiple optical fibers. Additionally, Patent Literatures 2 and 3describe an optical fiber ribbon (intermittently connected optical fiberribbon) in which three or more optical fibers in parallel areintermittently connected.

CITATION LIST Patent Literature

PTL 1: Japanese Patent Application Publication No. 2009-237480

PTL 2: Japanese Patent Application Publication No. 2016-1338

PTL 3: Japanese Patent Application Publication No. 2018-10238

As described in PTL 1, an optical fiber ribbon (a collective coatingtype optical fiber ribbon) in which multiple optical fibers are coatedcollectively has a structure that prevents a lateral pressure onto theoptical fibers, and therefore it is possible to inhibit the microbendingloss in the optical fibers. In contrast, the inventor of thisapplication found out that, in a case of an intermittently connectedoptical fiber ribbon as described in PTLs 2 and 3, the microbending lossin the optical fibers is increased under predetermined conditions.

SUMMARY

One or more embodiments of the present invention provides anintermittently connected optical fiber ribbon that is capable ofinhibiting the microbending loss.

One or more embodiments of the invention is an intermittently connectedoptical fiber ribbon, comprising: a plurality of optical fibers arrangedin a predetermined direction; and connecting portions thatintermittently connect two adjacent ones of the optical fibers, whereina peripheral resin portion is formed on a periphery of the opticalfibers, and an arithmetic mean roughness Ra of a surface of theperipheral resin portion is 0.41 μm or lower.

Other features of embodiments of the present invention will bedemonstrated by the description to be given below and by the drawings.

One or more embodiments of the present invention can inhibit themicrobending loss.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating an intermittently connected opticalfiber ribbon 1 in which single fibers are intermittently connected toone another according to one or more embodiments.

FIG. 2 is a diagram illustrating a different intermittently connectedoptical fiber ribbon 1.

FIG. 3 is a sectional view taken along X-X in FIG. 1.

FIG. 4A is a diagram illustrating a manufacturing system 100 formanufacturing the intermittently connected optical fiber ribbon 1, andFIGS. 4B and 4C are diagrams illustrating a ribbon forming apparatus 40.The ribbon forming apparatus 40 includes an application device 41, aremoval device 42, and a light source 43.

FIG. 5A is a diagram illustrating arithmetic mean roughness Ra and rootmean square height Rq. FIG. 5B is a diagram illustrating maximum heightRy. FIG. 5C is a diagram illustrating ten-point mean roughness Rz.

FIG. 6A is a diagram illustrating an intermittently connected opticalfiber ribbon 1 according to one or more embodiments. FIG. 6B is asectional view taken along X2-X2 in FIG. 6A.

DETAILED DESCRIPTION

At least the following matters are disclosed from the descriptions ofthe following specification and drawings.

An intermittently connected optical fiber ribbon will become clear,comprising: a plurality of optical fibers arranged in a predetermineddirection; and connecting portions that intermittently connect twoadjacent ones of the optical fibers, wherein a peripheral resin portionis formed on a periphery of the optical fibers, and an arithmetic meanroughness Ra of a surface of the peripheral resin portion is 0.41 μm orlower. According to such an intermittently connected optical fiberribbon, it is possible to inhibit the microbending loss.

An intermittently connected optical fiber ribbon will become clear,comprising: a plurality of optical fibers arranged in a predetermineddirection; and connecting portions that intermittently connect twoadjacent ones of the optical fibers, wherein a peripheral resin portionis formed on a periphery of the optical fibers, and a maximum height Ryof a surface of the peripheral resin portion is 2.0 μm or lower.According to such an intermittently connected optical fiber ribbon, itis possible to inhibit the microbending loss.

An intermittently connected optical fiber ribbon will become clear,comprising: a plurality of optical fibers arranged in a predetermineddirection; and connecting portions that intermittently connect twoadjacent ones of the optical fibers, wherein a peripheral resin portionis formed on a periphery of the optical fibers, and a ten-point meanroughness Rz of a surface of the peripheral resin portion is 1.4 μm orlower. According to such an intermittently connected optical fiberribbon, it is possible to inhibit the microbending loss.

An intermittently connected optical fiber ribbon will become clear,comprising: a plurality of optical fibers arranged in a predetermineddirection; and connecting portions that intermittently connect twoadjacent ones of the optical fibers, wherein a peripheral resin portionis formed on a periphery of the optical fibers, and a root mean squareheight Rq of a surface of the peripheral resin portion is 0.42 μm orlower. According to such an intermittently connected optical fiberribbon, it is possible to inhibit the microbending loss.

It is desirable that the peripheral resin portion is formed of resinforming the connecting portions. With this, it is possible to form aperipheral resin portion and a connecting portion from the same resin.

It is desirable that a silicone compound is added to the resin. Since asurface of the optical fiber ribbon 1 may be rough when anintermittently connected optical fiber ribbon is manufactured by usingresin to which a silicone compound is added, it is particularlydesirable in such a case to set the surface roughness of the peripheralresin portion to be a predetermined value or lower.

<Intermittently Connected Optical Fiber Ribbon>

FIG. 1 is a diagram illustrating an intermittently connected opticalfiber ribbon 1 in which single fibers are intermittently connected toone another.

The intermittently connected optical fiber ribbon 1 is an optical fiberribbon in which a plurality of optical fibers are arranged side by sideand intermittently connected together. Two adjacent optical fibers 2 areconnected by connecting portions 5. The plurality of connecting portionsthat connect two adjacent optical fibers 2 are disposed intermittentlyin the longitudinal direction. The plurality of connecting portions 5 inthe intermittently connected optical fiber ribbon 1 are intermittentlydisposed two-dimensionally in the longitudinal direction and the ribbonwidth direction. The connecting portions 5 are formed by applying anultraviolet light curable resin (a coupling agent) to serve as anadhesive and then curing the resin by application of ultraviolet light.Note that it is also possible to form the connecting portions 5 with athermoplastic resin. A non-connecting portion 7 is formed between theconnecting portion 5 and the connecting portion 5 that areintermittently formed in the longitudinal direction. In other words, theconnecting portion 5 and the non-connecting portion 7 are alternatelydisposed in the longitudinal direction. At the non-connecting portion 7,two adjacent optical fibers are not bound to each other. Thenon-connecting portion 7 is disposed in the ribbon width directionrelative to a position where the connecting portion 5 is formed. Thismakes it possible to roll the optical fiber ribbon 1 into a bundle andtherefore possible to house a large number of optical fibers 2 in anoptical cable with high density.

FIG. 2 is a diagram illustrating a different intermittently connectedoptical fiber ribbon 1. This optical fiber ribbon 1 includes a pluralityof (six here) pairs of two optical fibers 2 connected togethercontinuously in the longitudinal direction (fiber pairs 3), and adjacentfiber pairs 3 are connected together intermittently with the connectingportions 5. In this intermittently connected optical fiber ribbon 1 aswell, the non-connecting portion 7 is disposed in the ribbon widthdirection of a position where the connecting portion 5 is formed. Thismakes it possible to roll the optical fiber ribbon 1 into a bundle.Also, in this intermittently connected optical fiber ribbon 1 as well,the plurality of connecting portions 5 connecting adjacent fiber pairs 3are disposed intermittently in the longitudinal direction, and thenon-connecting portion 7 is formed between the connecting portion 5 andthe connecting portion 5. In other words, in this intermittentlyconnected optical fiber ribbon 1 as well, the connecting portion 5 andthe non-connecting portion 7 are alternately disposed in thelongitudinal direction.

Note that the intermittently connected optical fiber ribbon 1 is notlimited to the ones shown in FIGS. 1 and 2. For example, the arrangementof the connecting portions 5 may be changed, or the number of opticalfibers 2 may be changed.

FIG. 3 is a sectional view taken along X-X in FIG. 1.

Each optical fiber 2 is formed by an optical fiber bare wire 2A, acoating layer 2B, and a colored layer 2C. The optical fiber bare wire 2Ais formed by a core and a cladding. The coating layer 2B is a layercoating the optical fiber bare wire 2A. The coating layer 2B includes,for example, a primary coating layer (primary coating) and a secondarycoating layer (secondary coating). Note that, the Young's modulus of theprimary coating layer is 0.4 to 0.8 MPa, and the outer diameter thereofis 150 to 160 μm, while the Young's modulus of the secondary coatinglayer is 900 to 1300 MPa, and the outer diameter thereof is 190 to 200μm. The colored layer 2C is a layer formed on a surface of the coatinglayer 2B. The colored layer 2C is formed by applying a colorant on thesurface of the coating layer 2B. A marking may be formed between thecoating layer 2B and the colored layer 2C. The Young's modulus of thecolored layer 2C is 850 to 950 MPa, and the outer diameter thereof is200 to 210 μm. Note that, the colored layer 2C and a marking may not beformed on the outer side of the coating layer 2B (that is, the opticalfiber 2 may be formed of the optical fiber bare wire 2A and the coatinglayer 2B).

Between the two optical fibers 2, the connecting portion 5 is formed byapplying and curing the coupling agent (ultraviolet-curing resin). Inone or more embodiments, the coupling agent (ultraviolet-curing resin)is applied and cured also on a surface of the colored layer 2C of theoptical fiber 2. In the following descriptions, the resin (in this case,the cured coupling agent) formed on the periphery of the optical fiber 2(in this case, the periphery of the colored layer 2C) may be referred toas a “peripheral resin portion 8.” Additionally, the connecting portion5 (the cured coupling agent) and the peripheral resin portion 8 may becollectively referred to as a “ribbon forming material portion 9.”

Note that, in one or more embodiments, the peripheral resin portion 8 isformed of the resin (the coupling agent) forming the connecting portion5. However, as long as the peripheral resin portion 8 is resin formed onthe periphery of the optical fiber 2, the peripheral resin portion 8 maybe formed of resin other than the resin (the coupling agent) forming theconnecting portion 5.

Additionally, in one or more embodiments, the peripheral resin portion 8is formed on the entire periphery of the optical fiber 2. However, theperipheral resin portion 8 may not be formed on the entire periphery ofthe optical fiber 2 and may be formed on a part of the periphery of theoptical fiber 2.

Moreover, in one or more embodiments, the peripheral resin portion 8 isformed on the entire area of the optical fiber 2 in the longitudinaldirection. However, the peripheral resin portion 8 may not be formed onthe entire area of the optical fiber 2 in the longitudinal direction andmay be formed on a part of the optical fiber 2 in the longitudinaldirection.

FIG. 4A is a diagram illustrating a manufacturing system 100 formanufacturing the intermittently connected optical fiber ribbon 1. Forthe simplification of the drawing, the manufacturing system 100described here manufactures a four-fiber optical fiber ribbon.

The manufacturing system 100 has fiber supply devices 10, a printingapparatus 20, a coloring apparatus 30, a ribbon forming apparatus 40,and a bobbin 50.

The fiber supply devices 10 are devices (supply sources) that supply theoptical fibers 2. Here, the fiber supply device 10 supplies a singleoptical fiber 2 (an optical fiber formed by the optical fiber bare wire2A and the coating layer 2B; an optical fiber before the formation ofthe colored layer 2C). Alternatively, the fiber supply device 10 maysupply a pair of two optical fibers 2 (the fiber pair 3). The fibersupply device 10 supplies the optical fiber 2 to the printing apparatus20.

The printing apparatus 20 is an apparatus that prints a mark on theoptical fiber 2. For example, the printing apparatus 20 prints a markindicative of a ribbon number on each optical fiber 2. The plurality ofoptical fibers 2 marked by the printing apparatus 20 are supplied to thecoloring apparatus 30.

The coloring apparatus 30 is an apparatus that forms the colored layers2C of the optical fibers 2. The coloring apparatus 30 forms the coloredlayer 2C on each of the optical fibers 2 with an identification colorfor identification of the optical fiber 2. Specifically, the coloringapparatus 30 has coloring devices (not shown) for the respective opticalfibers 2, and the coloring devices each apply a coloring agent(ultraviolet light curable resin) of a predetermined identificationcolor to the surface of the corresponding optical fiber 2 (the surfaceof the coating layer 2B). The coloring apparatus 30 also has anultraviolet light irradiation device (not shown), and the ultravioletlight irradiation device applies ultraviolet light to the coloring agent(the ultraviolet light curable resin) applied to each optical fiber 2and cures the coloring agent, thereby forming the colored layer 2C. Theoptical fibers 2 colored by the coloring apparatus 30 are supplied tothe ribbon forming apparatus 40. Alternatively, the colored opticalfibers 2 may be supplied to the ribbon forming apparatus 40 from thefiber supply devices 10.

The ribbon forming apparatus 40 is an apparatus that manufactures theintermittently connected optical fiber ribbon 1 by forming theconnecting portions 5 intermittently. Supplied to the ribbon formingapparatus 40 are the plurality of optical fibers 2 arranged in the widthdirection. FIGS. 4B and 4C are diagrams illustrating the ribbon formingapparatus 40. The ribbon forming apparatus 40 has an application device41, a removal device 42, and light sources 43.

The application device 41 is a device that applies a coupling agent. Thecoupling agent is, for example, an ultraviolet light curable resin, andthe connecting portion 5 is formed by curing of the coupling agent. Theapplication device 41 applies the coupling agent in liquid form to theouter circumferences of the optical fibers 2 and to between adjacentones of the optical fibers 2 continuously in the longitudinal directionby inserting the plurality of optical fibers 2 through coating diesfilled with the liquid coupling agent. Note that, in one or moreembodiments, a silicone compound is added to the ultraviolet-curingresin forming the coupling agent in liquid form. Use of the couplingagent in which the silicone compound is added to the ultraviolet-curingresin makes it easy to remove the peripheral resin portion 8 from theoptical fiber 2 and makes it easy to perform the single fiber separationof the optical fibers 2 from the intermittently connected optical fiberribbon 1.

The removal device 42 is a device that removes part of the couplingagent applied by the application device 41 while leaving part thereof.The removal device 42 has rotary blades 421 each with a recessed portion421A (see FIG. 4B), and rotates the rotary blades 421 in conformity withthe speed at which the optical fibers 2 are supplied. While the couplingagent applied by the application device 41 is removed by being blockedby the outer edges of the rotary blades 421, the coupling agent is leftunremoved at the recessed portions 421A of the rotary blades 421. Thepart of the coupling agent left unremoved serves as the connectingportion 5 (see FIG. 1), and the part of the coupling agent removedserves as the non-connecting portion 7. Thus, the length and arrangementof the connecting portions 5 can be adjusted by adjustment of therotation speed of the rotary blade 421 and the size of the recessedportion 421A.

The light sources 43 are devices that apply ultraviolet light to thecoupling agent formed of the ultraviolet light curable resin. The lightsources 43 have temporary curing light sources 43A and a full curinglight source 43B. The temporary curing light sources 43A are disposedupstream of the full curing light source 43B. The coupling agenttemporarily cures when irradiated with ultraviolet light by thetemporary curing light sources 43A. The temporarily cured coupling agentis in a state of not being completely cured but being cured at thesurface. The full curing light source 43B causes the coupling agent tocure fully by applying stronger ultraviolet light than the temporarycuring light sources 43A. The fully cured ultraviolet light curableresin is in a state of being cured all the way through (although thefully cured coupling agent (the connecting portion 5) is moderatelyelastic, so that the intermittently connected optical fiber ribbon 1 canbe rolled into a tube).

As shown in FIG. 4C, the optical fibers 2 immediately out of theapplication device 41 and the removal device 42 are spaced apart fromeach other. In this state, the temporary curing light sources 43A applyultraviolet light to the coupling agent to temporarily cure the couplingagent. After the temporary curing of the coupling agent, the ribbonforming apparatus 40 gradually narrows the gaps between the opticalfibers 2 and arrange the plurality of optical fibers 2 side by side,concentrating them into a ribbon form. The coupling agent is alreadytemporarily cured; thus, even if the parts where the coupling agent hasbeen removed (the non-connecting portions 7) come into contact with eachother, they do not become connected together. Also, because the couplingagent is yet to be fully cured, the optical fibers 2 can be narrowed ingaps (concentrated) even at the regions connected with the couplingagent. Once the coupling agent cures fully by being irradiated withultraviolet light by the full curing light source 43B, theintermittently connected optical fiber ribbon 1 shown in FIG. 1A ismanufactured. Note that, as long as it is possible to form theconnecting portions 5 of the intermittently connected optical fiberribbon 1 intermittently, the light source 43 is not limited to the oneincluding two types of light sources, which are the light source forpreliminary curing 43A and the light source for final curing 43B, andfor example, the light source 43 may include one light source.

Note that, the above-described ribbon forming apparatus forms theconnecting portions 5 and the non-connecting portions 7 of theintermittently connected optical fiber ribbon 1 by removing a part ofthe coupling agent applied by the application device 41 while leavingsome parts. However, the method of intermittently forming the connectingportions 5 is not limited to this. For example, the ribbon formingapparatus 40 may form the intermittently connected optical fiber ribbon1 by, after applying the coupling agent so as to collectively coat themultiple optical fibers 1 and curing the coupling agent (that is, afteronce forming an optical fiber ribbon coated collectively), making anotch in the coupling agent cured between the optical fiber 1 and theoptical fiber 1. Additionally, the ribbon forming apparatus 40 may formthe intermittently connected optical fiber ribbon 1 by intermittentlyejecting the coupling agent from a dispenser to the optical fibers andcuring the coupling agent. Note that, in this case, the dispenser mayapply the coupling agent from two sides of a ribbon surface of theoptical fiber ribbon or may apply the coupling agent from one side ofthe ribbon surface. Moreover, the ribbon forming apparatus 40 may formthe intermittently connected optical fiber ribbon by applying thecoupling agent in the shape of a band as described later (see one ormore embodiments described below) or may form the intermittentlyconnected optical fiber ribbon by attaching a connecting ribbon in theshape of a band.

The bobbin 50 is a member that winds up the optical fiber ribbon 1 (seeFIG. 4A). The optical fiber ribbon 1 manufactured by the ribbon formingapparatus 40 is wound up by the bobbin 50.

As described above, in one or more embodiments, during the manufacturingof the intermittently connected optical fiber ribbon 1, the applicationdevice 41 applies the coupling agent in liquid form on the periphery ofthe optical fiber 2 and between the adjacent optical fibers 2.Additionally, in one or more embodiments, the silicone compound is addedto the ultraviolet-curing resin forming the coupling agent in liquidform. Use of the coupling agent in which the silicone compound is addedto the ultraviolet-curing resin makes it easy to remove the ribbonforming material portion 9 (the connecting portion 5 between the opticalfibers 2 and the cured coupling agent on the periphery of the opticalfiber 2) from the optical fiber 2 and makes it easy to perform thesingle fiber separation of the optical fibers 2 from the intermittentlyconnected optical fiber ribbon 1.

In the case where the intermittently connected optical fiber ribbon 1 ismanufactured by using the coupling agent in which the silicone compoundis added to the ultraviolet-curing resin, a surface of the optical fiberribbon 1 may be rough if the compatibility between theultraviolet-curing resin and the silicone compound is bad. The inventorof this application found out that, when a surface of the optical fiberribbon 1 is rough as described above, the microbending loss is increaseddue to the irregularities formed on the surface of the optical fiberribbon 1.

In order to inhibit the microbending loss in the optical fibers formingthe intermittently connected optical fiber ribbon, the smallirregularities on the surface of the optical fiber ribbon 1 (in otherwords, the small surface roughness of the peripheral resin portion 8 ofthe optical fiber 2) are desired. Specifically, in order to inhibit themicrobending loss in the optical fibers forming the intermittentlyconnected optical fiber ribbon, the arithmetic mean roughness Ra of theperipheral resin portion 8 of the optical fiber 2 is desired to be 0.41μm or lower. Additionally, in order to inhibit the similar microbendingloss, the maximum height Ry of the peripheral resin portion 8 of theoptical fiber 2 is desired to be 2.0 μm or lower. Moreover, in order toinhibit the similar microbending loss, the ten-point mean roughness Rzof the peripheral resin portion 8 of the optical fiber 2 is desired tobe 1.4 μm or lower. Furthermore, in order to inhibit the similarmicrobending loss, the root mean square height Rq of the peripheralresin portion 8 of the optical fiber 2 is desired to be 0.42 μm orlower. These points are described below.

<Arithmetic Mean Roughness Ra>

12-fiber intermittently connected optical fiber ribbons illustrated inFIG. 1 was created according to the manufacturing method illustrated inFIGS. 4A to 4C. Note that, the outer diameter of the primary coatinglayer (primary coating) forming the coating layer 2B (see FIG. 3) is 150to 160 μm, and the outer diameter of the secondary coating layer(secondary coating) is 190 to 200 μm. Additionally, the outer diameterof the colored layer 2C (see FIG. 3) is 200 to 210 μm. The Young'smodulus is 850 to 950 MPa. Moreover, the Young's modulus of the primarycoating layer in one or more embodiments is 0.4 to 0.8 MPa, and theYoung's modulus of the secondary coating layer is 900 to 1300 MPa.

Additionally, multiple types of the 12-fiber intermittently connectedoptical fiber ribbons were created with different types of couplingagents. In this case, as indicated in Table 1 below, multiple types ofthe 12-fiber intermittently connected optical fiber ribbon were createdby changing the Young's modulus of the coupling agent (the connectingportion 5, the peripheral resin portion 8, and the ribbon formingmaterial portion 9) and the silicone compound added to the couplingagent. Note that, the Young's modulus of the coupling agent was measuredby creating a sheet by irradiating the coupling agent(ultraviolet-curing resin) that is applied to have the film thickness of200 μm with ultraviolet light of the illuminance of 500 mJ/cm² under anitrogen-purged atmosphere, forming the sheet into the form of striphaving the width of 10 mm so as to form a specimen, and measuring themodulus of elasticity of the specimen under the strain of 2.5%. Theadded amount of the silicone compound is measured by analyzing the Siratio by SEM-EDS analysis of the coupling agent.

In order to measure the irregularities formed on the surface of theoptical fiber ribbon 1, the arithmetic mean roughness Ra was employed asan index indicating the surface roughness of the peripheral resinportion 8 of the optical fiber 2, and the arithmetic mean roughness Raof the peripheral resin portion 8 of the optical fiber 2 was measured.FIG. 5A is a diagram illustrating arithmetic mean roughness Ra. Thearithmetic mean roughness Ra is a value (unit: μm) that is obtained byan expression indicated in FIG. 5A when the roughness curve is expressedby y=f(x) where, the roughness curve in the standard length in thedirection of the average line is referred, the X axis is plotted in thedirection of the referred portion, and the Y axis is plotted in thedirection of the vertical magnification thereof. In this case, a compactsurface roughness measuring machine (Mitutoyo Corporation compactsurface roughness tester SJ-400) was used to measure the arithmetic meanroughness Ra of the peripheral resin portion 8 of the optical fiber 2according to the standards of JIS B0601 (1994). Additionally, after theconnecting portions of the optical fiber ribbon 1 were broken toseparate the optical fibers individually, the optical fibers were set inthe measuring machine so as to prevent the broken portions of theconnecting portions 5 from being measured portions, and the arithmeticmean roughness Ra in a range with the length of 10 mm in thelongitudinal direction on the surface of the peripheral resin portion 8of the optical fiber 2 was measured. The measurement was performed in 20portions of the optical fiber 2 (N=20), and the maximum value of thearithmetic mean roughness Ra of the surface of the peripheral resinportion 8 of the optical fiber 2 was measured.

Note that, in this case, the surface roughness of the peripheral resinportion 8 of the optical fiber 2 was measured along the longitudinaldirection of the optical fiber 2 (in other words, along a generatrix ofthe optical fiber 2 in the shape of cylindrical surface); however, thesurface roughness of the peripheral resin portion 8 of the optical fiber2 may be measured along the ribbon-width direction perpendicular to thelongitudinal direction. In this case, although the measurement result isaffected by the circular periphery shape of the optical fiber 2, thesurface roughness components can be extracted by removing the circularshape components from the measured curve (the roughness curve), and itis possible to measure the surface roughness (in this case, thearithmetic mean roughness Ra) based on the extracted surface roughnesscomponents. Note that, not only in the measurement of the arithmeticmean roughness Ra but also in the measurement of another surfaceroughness (for example, the maximum height Ry, the ten-point meanroughness Rz, the root mean square height Rq, and so on), the surfaceroughness may be measured along the longitudinal direction of theoptical fiber 2, or the surface roughness may be measured along theribbon-width direction perpendicular to the longitudinal direction.

For the evaluation of the optical fiber ribbon 1, the maximumtransmission loss at a low temperature of −40 degrees Celsius wasmeasured by the OTDR measurement. Note that, the maximum transmissionloss in the optical fiber ribbon 1 was measured while the optical fiberribbon 1 of 1000 m was loosely bundled by a rope to avoid the break upof the rolled bundle of the diameter of 300 mm (if the optical fiberribbon as the measurement target is too long, the transmission loss maybe increased due to an effect of the own weight of the bundle; for thisreason, in this case, the maximum transmission loss in the optical fiberribbon 1 of the length that has no effect of own weight (1000 m) wasmeasured). With the measured wavelength of 1.55 μm, the evaluation wasmade such that approve is obtained when the maximum transmission losswas 0.26 dB/km or lower and disapprove is obtained when the maximumtransmission loss was more than 0.26 dB/km (note that, the method ofmeasuring and the method of evaluating the transmission loss are similarfor the cases described below). The evaluation results were as indicatedin the following table.

TABLE 1 Added Amount Arithmetic Of The Mean Maximum Evaluation SiliconeRoughness Transmission Result Ribbon Young's Compound Ra Loss o: ApproveNumber Modulus [wt %] [μm] [dB/Km] x: Disapprove 1 1000 0.6 1.20 0.376 x2 550 1.0 1.43 0.409 x 3 433 0.6 0.95 0.356 x 4 1250 0.6 0.41 0.254 ○ 51307 0.6 0.09 0.209 ○ 6 1393 0.0 0.17 0.206 ○ 7 486 0.8 0.23 0.202 ○ 8334 0.8 0.13 0.205 ○ 9 372 0.8 0.19 0.202 ○ 10 307 0.8 0.08 0.192 ○ 11307 0.8 0.23 0.190 ○

As indicated in Table 1, when the arithmetic mean roughness Ra was 0.41μm or lower, the evaluation result was “approve.” Note that, even whenthe Young's modulus and the added amount of the silicone compound werevaried, there was no correlation of the Young's modulus and the addedamount of the silicone compound with the maximum transmission loss.Therefore, in order to inhibit the microbending loss in the opticalfiber forming the intermittently connected optical fiber ribbon, thearithmetic mean roughness Ra of the surface of the peripheral resinportion 8 of the optical fiber 2 is desired to be 0.41 μm or lower.

<Maximum Height Ry>

The maximum height Ry of the peripheral resin portion 8 of the opticalfiber 2 was measured while using the optical fiber ribbon 1 (the opticalfiber 2) in which the above-described arithmetic mean roughness Ra wasmeasured (that is, in this case, the maximum height Ry was employed asan index indicating the surface roughness of the peripheral resinportion 8 of the optical fiber 2). FIG. 5B is a diagram illustratingmaximum height Ry. The maximum height Ry is a value (unit: μm) that isobtained by referring the roughness curve in the standard length in thedirection of the average line and measuring an interval between the peakline and the valley line in the referred portion in the direction of thevertical magnification of the roughness curve. In the measurement of themaximum height Ry, the compact surface roughness measuring machine(Mitutoyo Corporation compact surface roughness tester SJ-400) was alsoused to measure the maximum height Ry of the peripheral resin portion 8of the optical fiber 2 according to the standards of JIS B0601 (1994).Additionally, after the connecting portions of the optical fiber ribbon1 were broken to separate the optical fibers individually, the opticalfibers were set in the measuring machine so as to prevent the brokenportions of the connecting portions 5 from being measured portions, andthe maximum height Ry in a range with the length of 10 mm in thelongitudinal direction on the surface of the peripheral resin portion 8of the optical fiber 2 was measured. The measurement was performed in 20portions of the optical fiber 2 (N=20), and the maximum value of themaximum height Ry of the surface of the peripheral resin portion 8 ofthe optical fiber 2 was measured. The evaluation results of the opticalfiber ribbon 1 in this case were as indicated in the following table.

TABLE 2 Added Amount Of The Maximum Maximum Evaluation Silicone HeightTransmission Result Ribbon Young's Compound Ry Loss o: Approve NumberModulus [wt %] [μm] [dB/Km] x: Disapprove 1 1000 0.6 5.5 0.376 x 2 5501.0 6.1 0.409 x 3 433 0.6 4.3 0.356 x 4 1250 0.6 1.8 0.254 ○ 5 1307 0.60.8 0.209 ○ 6 1393 0.0 0.9 0.206 ○ 7 486 0.8 1.3 0.202 ○ 8 334 0.8 0.70.205 ○ 9 372 0.8 1.0 0.202 ○ 10 307 0.8 1.1 0.192 ○ 11 307 0.8 2.00.190 ○

As indicated in Table 2, when the maximum height Ry was 2.0 μm or lower,the evaluation result was “approve.” Note that, even when the Young'smodulus and the added amount of the silicone compound were varied, therewas no correlation of the Young's modulus and the added amount of thesilicone compound with the maximum transmission loss. Therefore, inorder to inhibit the microbending loss in the optical fiber forming theintermittently connected optical fiber ribbon, the maximum height Ry ofthe surface of the peripheral resin portion 8 of the optical fiber 2 isdesired to be 2.0 μm or lower.

<Ten-Point Mean Roughness Rz>

The ten-point mean roughness Rz of the peripheral resin portion 8 of theoptical fiber 2 was measured by using the optical fiber ribbon 1 (theoptical fiber 2) in which the above-described arithmetic mean roughnessRa (and the maximum height Ry) was measured (that is, in this case, theten-point mean roughness Rz was employed as an index indicating thesurface roughness of the peripheral resin portion 8 of the optical fiber2). FIG. 5C is a diagram illustrating ten-point mean roughness Rz. Theten-point mean roughness Rz is a value (unit: μm) that is obtained byreferring the roughness curve in the standard length in the direction ofthe average line and adding an average value of absolute values of theattitudes of the highest peak to the fifth-highest peak (Yp1 to Yp5) andan average value of absolute values of the valleys of the lowest valleyto the fifth-lowest valley (Yv1 to Yv5), which are measured from theaverage line of the extracted portion in the direction of the verticalmagnification. In the measurement of the ten-point mean roughness Rz,the compact surface roughness measuring machine (Mitutoyo Corporationcompact surface roughness tester SJ-400) was also used to measure theten-point mean roughness Rz of the peripheral resin portion 8 of theoptical fiber 2 according to the standards of JIS B0601 (1994).Additionally, after the connecting portions of the optical fiber ribbon1 were broken to separate the optical fibers individually, the opticalfibers were set in the measuring machine so as to prevent the brokenportions of the connecting portions 5 from being measured portions, andthe ten-point mean roughness Rz in a range with the length of 10 mm inthe longitudinal direction on the surface of the peripheral resinportion 8 of the optical fiber 2 was measured. The measurement wasperformed in 20 portions of the optical fiber 2 (N=20), and the maximumvalue of the ten-point mean roughness Rz of the surface of theperipheral resin portion 8 of the optical fiber 2 was measured. Theevaluation results of the optical fiber ribbon 1 in this case were asindicated in the following table.

TABLE 3 Added Amount Ten-Point Of The Mean Maximum Evaluation SiliconeRoughness Transmission Result Ribbon Young's Compound Rz Loss o: ApproveNumber Modulus [wt %] [μm] [dB/Km] x: Disapprove 1 1000 0.6 4.4 0.376 x2 550 1.0 4.8 0.409 x 3 433 0.6 3.1 0.356 x 4 1250 0.6 1.3 0.254 ○ 51307 0.6 0.5 0.209 ○ 6 1393 0.0 0.8 0.206 ○ 7 486 0.8 1.0 0.202 ○ 8 3340.8 0.5 0.205 ○ 9 372 0.8 0.8 0.202 ○ 10 307 0.8 0.9 0.192 ○ 11 307 0.81.4 0.190 ○

As indicated in Table 3, when the ten-point mean roughness Rz was 1.4 μmor lower, the evaluation result was “approve.” Note that, even when theYoung's modulus and the added amount of the silicone compound werevaried, there was no correlation of the Young's modulus and the addedamount of the silicone compound with the maximum transmission loss.Therefore, in order to inhibit the microbending loss in the opticalfiber forming the intermittently connected optical fiber ribbon, theten-point mean roughness Rz of the surface of the peripheral resinportion 8 of the optical fiber 2 is desired to be 1.4 μm or lower.

<Root Mean Square Height Rq>

The root mean square height Rq of the peripheral resin portion 8 of theoptical fiber 2 was measured by using the optical fiber ribbon 1 (theoptical fiber 2) in which the above-described arithmetic mean roughnessRa and the like were measured (that is, in this case, the root meansquare height Rq was employed as an index indicating the surfaceroughness of the peripheral resin portion 8 of the optical fiber 2). Theroot mean square height Rq is a value (unit: μm) representing the rootmean square in the standard length based on the expression indicated inFIG. 5A and is a value indicating the standard deviation of the surfaceroughness. In the measurement of the root mean square height Rq, thecompact surface roughness measuring machine (Mitutoyo Corporationcompact surface roughness tester SJ-400) was also used to measure theroot mean square height Rq of the peripheral resin portion 8 of theoptical fiber 2 according to the standards of JIS B0601. Additionally,after the connecting portions of the optical fiber ribbon 1 were brokento separate the optical fibers individually, the optical fibers were setin the measuring machine so as to prevent the broken portions of theconnecting portions 5 from being measured portions, and the root meansquare height Rq in a range with the length of 10 mm in the longitudinaldirection on the surface of the peripheral resin portion 8 of theoptical fiber 2 was measured. The measurement was performed in 20portions of the optical fiber 2 (N=20), and the maximum value of theroot mean square height Rq of the surface of the peripheral resinportion 8 of the optical fiber 2 was measured. The evaluation results ofthe optical fiber ribbon 1 in this case were as indicated in thefollowing table.

TABLE 4 Added Amount Of The Root Mean Maximum Evaluation Silicone SquareTransmission Result Ribbon Young's Compound Height Rq Loss o: ApproveNumber Modulus [wt %] [μm] [dB/Km] x: Disapprove 1 1000 0.6 1.46 0.376 x2 550 1.0 1.69 0.409 x 3 433 0.6 1.13 0.356 x 4 1250 0.6 0.42 0.254 ○ 51307 0.6 0.12 0.209 ○ 6 1393 0.0 0.20 0.206 ○ 7 486 0.8 0.29 0.202 ○ 8334 0.8 0.15 0.205 ○ 9 372 0.8 0.25 0.202 ○ 10 307 0.8 0.13 0.192 ○ 11307 0.8 0.33 0.190 ○

As indicated in Table 4, when the root mean square height Rq was 0.42 μmor lower, the evaluation result was “approve.” Note that, even when theYoung's modulus and the added amount of the silicone compound werevaried, there was no correlation of the Young's modulus and the addedamount of the silicone compound with the maximum transmission loss.Therefore, in order to inhibit the microbending loss in the opticalfiber forming the intermittently connected optical fiber ribbon, theroot mean square height Rq of the surface of the peripheral resinportion 8 of the optical fiber 2 is desired to be 0.42 μm or lower.

FIG. 6A is a diagram illustrating an intermittently connected opticalfiber ribbon 1 according to one or more embodiments. FIG. 6B is asectional view taken along X2-X2 in FIG. 6A.

In one or more embodiments, the optical fiber ribbon 1 is also anoptical fiber ribbon in which the multiple optical fibers 2 are inparallel and intermittently connected. In one or more embodiments, theribbon forming material portion 9 is formed in the shape of a bandhaving a width L by applying the coupling agent on the ribbon surface (asurface parallel in the longitudinal direction and in the widthdirection) of the optical fiber ribbon 1 in the shape of a band andcuring the coupling agent. The connecting portion 5 is formed betweentwo optical fibers 2 with the coupling agent being applied and curedbetween the two optical fibers 2. Additionally, the peripheral resinportion 8 is formed on the periphery of the optical fiber 2 with thecoupling agent being applied and cured on the periphery of the opticalfiber 2. The multiple connecting portions 5 connecting adjacent twooptical fibers 2 are intermittently arranged in the longitudinaldirection in one or more embodiments as well. Moreover, the multipleconnecting portions 5 of the intermittently connected optical fiberribbon 1 are intermittently arranged two-dimensionally in thelongitudinal direction and the ribbon-width direction. Thenon-connecting portion 7 is formed between the connecting portion 5 andthe connecting portion 5 which are intermittently formed in thelongitudinal direction. In the non-connecting portions 7, the adjacenttwo optical fibers are not restrained with each other in one or moreembodiments as well.

The peripheral resin portion 8 in one or more embodiments is formed on apart of the periphery of the optical fiber 2 (in contrast, theperipheral resin portion 8 in the above-described embodiments is formedon the entire periphery of the optical fiber 2). Additionally, theperipheral resin portion 8 in one or more embodiments is formed on apart of the optical fiber 2 in the longitudinal direction (in contrast,the peripheral resin portion 8 in one or more above-describedembodiments is formed on the entire area of the optical fiber 2 in thelongitudinal direction).

When a surface of the optical fiber ribbon 1 is rough in the portion inwhich the peripheral resin portion 8 is formed, the microbending loss isincreased due to the irregularities formed on the surface of the opticalfiber ribbon 1 in one or more embodiments as well. In order to inhibitsuch microbending loss, it is desired in the one or more embodiments aswell for the irregularities on the surface of the optical fiber ribbon 1to be small as with the above-described embodiments. Therefore, in orderto inhibit the microbending loss in the optical fiber forming theintermittently connected optical fiber ribbon, the arithmetic meanroughness Ra of the peripheral resin portion 8 of the optical fiber 2 isdesired to be 0.41 μm or lower in one or more embodiments as well.Additionally, in order to inhibit the similar microbending loss, themaximum height Ry of the peripheral resin portion 8 of the optical fiber2 is desired to be 2.0 μm or lower. Moreover, in order to inhibit thesimilar microbending loss, the ten-point mean roughness Rz of theperipheral resin portion 8 of the optical fiber 2 is desired to be 1.4μm or lower. Furthermore, in order to inhibit the similar microbendingloss, the root mean square height Rq of the peripheral resin portion 8of the optical fiber 2 is desired to be 0.42 μm or lower.

Note that, in above-described embodiments, the peripheral resin portion8 is formed of the ribbon forming material portion (the resin formingthe connecting portion 5). However, even when the peripheral resinportion is not the ribbon forming material portion 9, if a surface ofthe peripheral resin portion formed on the periphery of the opticalfiber 2 is rough, the microbending loss is increased due to theirregularities. For this reason, the surface roughness of the peripheralresin portion of the optical fiber 2 is desired to be a predeterminedvalue or lower as with the above-described embodiments in the case wherethe peripheral resin portion is not the ribbon forming material portionas well.

Although the disclosure has been described with respect to only alimited number of embodiments, those skilled in the art, having benefitof this disclosure, will appreciate that various other embodiments maybe devised without departing from the scope of the present invention.Accordingly, the scope of the invention should be limited only by theattached claims.

REFERENCE SIGNS LIST

-   1 optical fiber ribbon-   2 optical fiber-   2A optical fiber bare wire-   2B coating layer-   2C colored layer-   3 fiber pair-   5 connecting portion-   7 non-connecting portion-   8 peripheral resin portion-   9 ribbon forming material portion-   10 fiber supply device-   20 printing apparatus-   30 coloring apparatus-   40 ribbon forming apparatus-   41 application device-   42 removal device-   421 rotary blade-   421A recessed portion-   43 light source-   43A light source for preliminary curing-   43B light source for final curing-   50 bobbin

1. An intermittently connected optical fiber ribbon, comprising: aplurality of optical fibers arranged in a predetermined direction; andconnecting portions that intermittently connect two adjacent ones of theoptical fibers, wherein a peripheral resin portion is formed on aperiphery of the optical fibers, and an arithmetic mean roughness Ra ofa surface of the peripheral resin portion is 0.41 μm or lower.
 2. Anintermittently connected optical fiber ribbon, comprising: a pluralityof optical fibers arranged in a predetermined direction; and connectingportions that intermittently connect two adjacent ones of the opticalfibers, wherein a peripheral resin portion is formed on a periphery ofthe optical fibers, and a maximum height Ry of a surface of theperipheral resin portion is 2.0 μm or lower.
 3. An intermittentlyconnected optical fiber ribbon, comprising: a plurality of opticalfibers arranged in a predetermined direction; and connecting portionsthat intermittently connect two adjacent ones of the optical fibers,wherein a peripheral resin portion is formed on a periphery of theoptical fibers, and a ten-point mean roughness Rz of a surface of theperipheral resin portion is 1.4 μm or lower.
 4. An intermittentlyconnected optical fiber ribbon, comprising: a plurality of opticalfibers arranged in a predetermined direction; and connecting portionsthat intermittently connect two adjacent ones of the optical fibers,wherein a peripheral resin portion is formed on a periphery of theoptical fibers, and a root mean square height Rq of a surface of theperipheral resin portion is 0.42 μm or lower.
 5. The intermittentlyconnected optical fiber ribbon according to any one of claims 1 to 4,wherein the peripheral resin portion is formed of resin forming theconnecting portions.
 6. The intermittently connected optical fiberribbon according to any one of claims 1 to 5, wherein a siliconecompound is added to the resin.